Bulldozer attachment for tractors



A ril 14, 1953 J. w. MERZ BUL'LDOZER 'ATTACHMENT FOR TRACTORS 4 Sheets-Sheet 1 Filed March 14, 1949 3maentoi t/o/m M llerz (Ittorneg A 1953 J. w. MERZ BULLDOZER ATTACHMENT FOR TRACTORS 4 Sheets-Sheet 5 Filed March 14, 1949 N Zhmentor M/Verz Patented Apr. 14, 1953 UNITED STATES PATENT OFFICE BULLDOZER ATTACHMENT FOR TRACTORS John W. Merz, Belton, Mont.

Application March 14, 1949, Serial No. 81,245

3 Claims. 1

This invention relates to a bulldozer which constitutes an attachment for a tractor and it is one object of the invention to provide a bulldozer which may be applied to a tractor of conventional construction and have its blade disposed across the front of the tractor and operate upon ground in front of the tractor as the tractor moves forwardly.

Another object of the invention is to provide the bulldozer with a blade so connected with a frame which straddles the tractor that the blade may be tilted vertically and also have its ends shifted forwardly so that the blade may be angularly adjusted and caused to extend across the front of the tractor at a desired incline.

Another object of the invention is to provide a bulldozer carried by a frame which straddles a tractor and has its side arms pivotally mounted at opposite sides of the tractor, the arms of the frame being supported from bell crank levers pivoted to the tractor and moved to adjusted positions by hydraulic means so located that the operator of the tractor may actuate the hydraulic means without descending from the tractor.

Another object of the invention is to provide a bulldozer which is of simplified construction and may be very easily mounted upon a tractor and also easily removed when the tractor is to be used for other purposes.

The invention is illustrated in the accompanying drawings wherein:

Fig. 1 is a side elevation showing the improved bulldozer mounted upon a tractor.

Fig. 2 is a perspective view upon an enlarged scale showing the manner in which ends of the blades are mounted for horizontal movement transversely of the tractor.

Fig. 3 is a top plan view of the blade and mechanism which adjustably connects the blade with the front end of the frame.

Fig. 4 is a view similar to Figure 3 showing portions in horizontal section.

Fig. 5 is a fragmentary sectional view taken along the line 5-5 of Figure 3.

Fig. 6 is a side elevation of the bulldozer.

This improved bulldozer consists briefly of a frame l adapted to be mounted in straddling relation to the forward portion of a tractor 2 and a blade 3 extending transversely of the front end of the frame and pivotally connected therewith so that the blade may be moved horizontally to angularly adjusted positions.

The frame I has hollow side bars 5 and a hollow cross bar 5 having rearwardly directed ends 6 through which are mounted sleeves I extending longitudinally of the side bars and fitting connected with lower ends of links 28.

2 about pins or stub shafts 3 which extend longitudt'nally of the side bars in axial relation thereto and have inner end portions welded to anchoring plates mounted'in the side bars. Thrust bearings it are mounted about the pins between confronting ends of the side bars and the cross bar and nuts i i which are applied to the threaded front ends of the pins hold ends of the cross bar upon the pins. By properly adjusting the nuts the ends of the cross bar will be allowed to turn about the pins and the cross bar may therefore have pivotal movement when the side bars are individually tilted or one side bar tilted upwardly while the other is tilted downwardly and the cross bar may be moved vertically from a horizontal position to a raised position, as indicated by dotted lines in Figure 1. Upper and lower plates or brackets it which are welded to the cross bar midway the length thereof project forwardly from the cross bar and at their front ends are formed with openings 13 to receive pivot pins M which also pass through openings id in ears l6 projecting rearwardly from the blade midway the length thereof one above the other. By so mounting the blade it may be moved horizontally about a vertical axis and swung in either direction to an angularly adjusted position, as indicated by dotted lines in Figure 3. The side bars of the frame l have their rear ends pivotally mounted about stub shafts or pivot pins I! which project from opposite sides of the tractor and adjacent their front ends the side bars carry upwardly projecting ears l8v through which pass pins is by means of which the arms are pivotally These links have their upper ends pivotally connected with the horizontally extending arms of bell crank levers 26 mounted at opposite sides of the tractorv and the vertical arms of these levers are connectedwith outer ends of piston rods 22 projecting forwardly'from cylinders 23. The cylinders are pivoted to standards 24 and with front and rear end portions of each cylinder are connected tubes 25 and 26 so that liquid may be passed through the cylinders in the usual manner by the operator of the tractor and the-pistons and their rods shifted longitudinally to efiect vertical swinging movement of the arms l to adjusted positions. When both cylinders are energized and their pistons moved in the same direction the frame willbe swung vertically from each side and raised or lowered in a horizontal position ac"- cording to the direction in which the pistons are moved. Where only one cylinder is energized one side arm 4 of the frame will be shifted upwardly or downwardly and the-blade tilted transversely of the frame in a vertical direction to an angularly adjusted position. It will thus be seen that the blade may be shifted vertically to adjusted positions and either held in a horizontal position or moved transversely of the tractor to angularly adjusted positions. The fact that the ends of the cross bar are pivotally connected with the side arms allows angular adjustment without distorting the 1 side arms or the cross bar, and provision of the thrust bearings Ill allows movement of the cross bar to take place very easily.

In order to angularly za'djnst thabla'de :and move it from the position shown in full lines in Figure 3 to a diagonally extending position, such as indicated by dotted lines inithis figure, it"must be moved about the pins I4. In order that this may be accomplished ends of the blade'are connected with the frame l- -by yokes 21 and 28. The 'yokes 2-! are pivotally mounted"between'bearing plates or brackets 29- welded to ends of the cross "bar 5by pins 19' and the iyokes I28 are .pivotally mounted 'between ears 30' by pins-3t. Armsof the companion yokesproject towards each'other and are'pivotally connected by pins-31 thus forming hinge joints of the :toggle type which allow the yokes to be :swungfrom' a position in which theyare in end to endxali'gnm'ent with each other to'an inwardly foldedposition. When the yokes are in the partially .folded position shown in :Figure 3 the blade "will :be'fheld at right angles to thelengthiof .thetractor andpush dirt straight ahead of :the tractor. By swinging the :yokes at oneside ofithe frame outwardly towards the ex- :tended positionfia'nd swinging the yokes .at the other z'side'of'the frame inwardly in a folding "direction the "blade will have one end thrust forwardly'andrits'other enddrawn rearwardly and the blade will be movedabout the pins hi to an tinclined position and as "the "tractor is moved forwardly dirt 'encountere'd by :the blade will be pushed forwardly Land at :the :same time slide .alOng the blade'towards'the rear end :thereof and pass .fromthe 'rblade "at this irea'r'fend. A cylinder 32 extends tatransversely of the frame and is tpivotally mounted between the plates :12 :byzpinsSS. A.piston;rod.34 is s'li-dable longitudinally "through the :tcylinder' and has its end portions projectingioutwardlyfrom opposite ends of the cylinder :and carrying;yokes 35. Front and rear :arms or links 36 :are :pivotally connected with thezyokes by pins Mi-and these linkshave their 'outer: ends." formed with" vertically extend- :ing lcrossheads 38 which 'areiofitubular -formation sand pivotally mounted between the arms of the yokes 28 byzpins :39. :A' piston 4058111- l-rounds the :rod:or:=shaftl;34:midway the length thereof :and :is .located the cylinder 32, and when this ,tzpi'ston :is moved longitudinally of 'thecylinder by, .liquid fed 60117118 cylinder by a suitable pump the-rod will be shifted longitudinally to-foldtheyokes at onezside of theframe rand extends-those at-the other: side "of the :frame .and thereby-cause .the blade :to be tilted about the-vertically extending gpins M to an'angularly adjusted position. Themechani'sm for-controlling flow of liquid to andfrom the cylinders .will ,be ;-of.conventional :constructiomand so located .upjon .thetractor-thatthe drivermaylreadily :reach the v:same 7 without leaving thee-seat, lbutlhas not :been .shownras zany conventionally constructed control mechanism may-be :used.

.Having thus described-the invention, what :claimed is 2 v 1. .A bulldozer attachment :foria tractor :com-

prising a frame of dimensions adapting it to straddle a tractor and having a cross bar for extending across the front end of the tractor and rearwardly extending side bars adapted to be pivoted at their rear ends to opposite sides of the tractor and mount the frame for vertical swinging movement to raised and lowered positions, means for swinging theframe-vertically to adjusted positions, a blade extending transversely of the frame in advance of the front end of the frame and pivoted midway of its length to the cross bar midway of the width of the frame for adjustment about a vertical axis to angularly adjusted positions, companion yokes pivoted to ends of the cross bar and the blade and extending towards each other with their meeting ends pivoted to each other for movement from a folded position to an extended position in alignment with each other to limit movement of the blade about its vertical axis, a mechanism connected with the yokes for moving the-yokes at 'one end of the blade'towards an extended position-while the yokes at the other end of the blade move towards a folded position-and thus angularlyadjust the blade.

2. A bulldozer attachment for a tractor comprising a frame of dimensions adapting it to straddle a tractor and havinga cross bar for extending across the front end of the tractor and rearwardly extending side bars adapted to be pivoted at their rear ends 'to'opposite sides of the tractor and mount the frame for vertical swinging movement to raised and lowered positions, ends of the cross bar being pivoted to front ends of the side bars for movement about a horizontal axis, means for independently swinging the side bars vertically and effecting movement "of the cross bar transversely of the tractor to angularly adjusted positions, a blade extending transversely of the frame, in front of the cross bar, upper and lower bearing-plates projectingforwardly from the'eross bar midway of the length thereof, upper and lower ears extending rearwardly from said *blade "midway of the length thereof and disposed between the bearingplates,

pins passing vertically through companion upper "and lower bearing platesand ears and mount- 'straddle a tractor and having a cross'bar'for extending across the'front end of 'the tractor and rearwardly extendin side bars adapted to be pivoted at their rear ends to opposite sides ofthe tractor and mount the'frame'forvertical swinging movement to raised and lowered positions, ends of the crossbar-being pivoted to front ends of the side bars for movement about a'horizontal axis, means for independently swinging the side .bars vertically and effecting movement "of the :cross bar transversely of the tractorto angularly adjusted positi'ons a blade extending transverse- ,l-y of theframe, in front of the'crossbar, upper and lower bearing plates projecting forwardly from the cross barniidway of the'lengthfthereof, upper and lower ears extending rearwardlyfrom :said blademidway of the length thereof and disposed between the *bearing plates, gpi'ns ,rpassinjg vertically 'zthrough--companion upper and lower bearing plates and ears and mounting the blade for horizontal swinging movement to angularly adjusted positions, companion front and rear yokes pivoted to each other and to ends of the blade and the cross bar, a cylinderextending transversely of said frame disposed between the bearing plates and pivotally mounted for movement about a vertical axis by pins passing through the said bearing plates, a rod passing longitudinally through said cylinder and projecting from opposite ends thereof, a piston carried by said rod within the cylinder and acted upon by fluid in the cylinder to shift the bar longitudinally, and links having inner ends pivotally connected with ends of said bar for horizontal swinging movement and having outer ends pivotally connected with the front and rear yokes ,for swinging the yokes at one side of the frame inwardly and the yokes at the other sides of the frame outwardly When the bar is shifted longitudinally and thereby move the blade about 5 its vertical aXis to angularly adjusted positions.

JOHN W. MERZ.

References Cited in the file of this patent 10 UNITED STATES PATENTS Number Name Date 910,384 Ireland Jan. 19, 1909 2,064,022 Maloon Dec. 15, 1936 15 2,075,482 Thorpe Mar. 30, 1937 2,160,595 Le Bleu May 30, 1939 2,173,158 Corbett Sept. 19, 1939 

